Screen mill



June 25, 1968 H. o. SCHUTTE SCREEN MILL 2 Sheets-Sheet 1 Filed May 17,1965 INVENTOR BY HERMAN o. SCHUTTE ATTORNEYS June 25, 1968 H. D. SCHUTTESCREEN MILL Filed May 17, 1965 2 Sheets-Sheet 2 l N VENTOR.

HERMAN'D. SCHUTTE United States Patent 3,389,862 SCREEN MILL Herman D.Schutte, 51 Woodbury Drive,

Snyder, N.Y. 14226 1 Filed May 17, 1965, Ser. No. 456,294 3 Claims. (Cl.241-86) ABSTRACT OF THE DISCLOSURE A screening mill consisting of ahousing into which a rotor shaft extends having a plurality of hammerspivotally carried thereon describing a cylindrically shaped hammer tippath plane concentric to said rotor shaft within said housing, amaterial sizing screen of spiral-shaped profile mounted interiorly ofsaid housing in substantially concentric relation to said tip plane pathand comprising a perforated plate bent into a spiraloid form with itsopposite ends disposed in spaced-apart relation and thereby defining amaterial inlet opening through a top portion of said screen into theinterior thereof, and amaterial feed chute leading through an aperturedtop portion of said housing and delivering mill feed through said inletopening into the interior of said screen and on top of said hammers.

This invention relates to screen mills as in the case of US. Patents No.2,328,170 and 2,532,262; and more particularly to further improved meansfor screen arrangernents therein.

A primary object of the present invention is to provide a pulverizer ofthe hammer mill type having an improved mill feed and product sizingscreen arrangement.

Another object of the invention is to provide a mill of the characterdescribed having an improved form of mill feeding and product screeningarrangement where the screen element is adapted to be mounted anddemounted with respect to the mill casing in an improved manner.

Another object of the invention is to provide in a mill of the characterdescribed improved means for detachably locking the product screeningmember in operative position relative to the mill frame.

Other objects and advantages of the invention will appear in thespecification hereinafter.

In the drawing:

FIG. 1 is a side elevation of a hammer mill of the invention showing bybroken lines the screen member thereof in mounted position;

FIG. 2 is a right hand end elevational view of the machine of FIG. 1,with a portion of the mill casing broken away to show the interiorthereof;

FIGS. 3, 4, are sectional views taken as suggested by lines 33 and 4-4,respectively, of FIG. 2; and

FIG. 5 is an inside perspective view of a screen holding component ofthe machine of the invention.

The drawings illustrate the invention by way of example in connectionwith a hammer mill of the type that is adapted particularly for grindingor pulverizing grain or other commodities; and as shown herein the millcomprises essentially a base carrying bearing blocks 12 for rotatablysupporting the rotor shaft 14. The rotors 16 are carried by the shaft 14and in turn each mounts a series of hammers 18 which are pivotallyconnected to the rotors so as to revolve in radially extended relationtherefrom. Heads may be carried by the hammers 18 if desired by means ofthe connection apertures 20, to receive the majority of the wear inconnection with processing of the mill feed. The mill casing is ofmodified rectangular form, and is fabricated of sheet metal to atentedJune 25, 1968 ice P comprise a back plate 22 and a horseshoe-shapedperipheral end and top cover portion 24. At the lower corner endportions of the casing, relatively short bottom plates 26, 26, areprovided and the structure is braced by means of diagonally disposedbaffle plates 28 welded to the adjacent end plate and bottom plate parts(FIGS. 3, 4). Thus, a discharge opening 30 for the screened product ofthe mill is provided at the center base portion of the casing. The millfeed supply device may be of any suitable form, but as illustratedherein includes a generally standard type gravity feed hopper designated32. A vertically adjustable slide plate 34 which is manualy movable asby means of a control arm 35 may be employed to variably throttle thesize of the outlet opening into the mill casing.

Whereas in some prior type mill constructions provision is made fordelivery of the mill feed material through a window in a side wallportion of the casing, the mill feed material is thereby directed tofall primarily against the hammers at that side of the mill. This isdisadvantageous because some of the rotors will flood with feedmaterial, while others rotate idly. Hence, the mill operation is notefficient. Also, in this case some of the rotors and rotor hammers aresubjected to excessive wear, and the maintenance and repair problems aremost trouble-some. On the other hand, it is a particular feature of thepresent invention that the mill feed delivers into the top of the millcasing in the form of a stream spread uniformly transversely of theentire inside width of the mill casing, as best shown in FIG. 2. Byvirtue of this arrangement the incoming mill feed material is deliveredby gravity to fall directly on top of all of the hammers of the mill, inevenly distributed manner thereover.

To accommodate this advantageous full width mill feed system while atthe same time obtaining the advantages of a substantially 360 degreesscreening area, I provide a spiraloid-shaped screen as indicated at saidscreen having a short gap in the periphery thereof through which themill feed material passes to the interior of the screen. Hence, thescreen may be formed into a generally cylindrical form and slip-fittedat one of its side edges into a grooved track device 42 which isembodied in the inner side wall portion of the casing back plate 22. Thetrack 42 is shaped as shown in FIG. 3 to encircle the tip paths of therotor hammers as the mill operates, while avoiding interference withinlet delivery of the mill feed material. For this purpose the feedhopper is formed with a delivery spout portion 44 (FIG. 3) whichdischarges the feed material as shown into the interior of the screen 40and into the zone of hammer rotation uniformly across the entire Widthof the mill interior. Thus the hammers pick up the mill feed materialand pound it against the inside of the screen 40 until such time as itpasses through the screen and then falls down and out of the millthrough the bottom opening, as illustrated by the flow directionalarrows in FIG. 3. Note that the spiral shaped screen member 40 includesan elfective screening length of the order of a full 360 circle screen.

To close the other side of the screen 40, a closure plate 46 may beemployed as best shown in FIG. 5, which is shaped to complement theperipheral configuration of the screen 40. The plate 46 includes ledgedevices as indicated at 48, thereby providing a grooved track into whichthe outer edge of the screen slip-fits. The plate 46 preferably includesan upstanding hanger portion 50 which is perforated as indicated at 52so that the plate 46 may be hung by means of a pin 54 upon a dependingbracket portion 56 extending fro-m the mill casing. Thus, the closureplate 46 is guided to stand in proper operative position to close theouter side of the cylindrical screen 40.

To hold the closure plate 46 in operative position and to simultaneouslyseal the mill casing against escape of material, a casing doordesignated 60 is swung as by means of hinges 62 relative to the casingstructure, and door holding clamps as indicated at 64, 64, are providedto cam-lock the door in tightly sealed relation on the casing. The door69 is radially ribbed as indicated at 66 to stiffen the door structure,and machine screws 68 are threaded through the door to bear at theirinner ends against the closure plate 46 whenever the door 60 is inclosed, locked position. Thus, from externally of the door the handscrews 68 may be turned down so as to firmly press the closure plateagainst the edge of the screen, thereby insuring its maintenance inoperative position.

I claim:

1. In a screening mill, in combination,

a housing having opposite side walls and a cover extending between saidside walls,

a horizontally disposed rotor shaft projecting into said housing throughone of said side walls,

a plurality of hammers pivotally carried by said rotor shaft within saidhousing and describing a cylindrically shaped hammer tip plane pathconcentrically of said rotor shaft when rotating therewith,

a material sizing screen of spiral-shaped profile and extending betweensaid side walls, said screen being perforate throughout and being spacedthroughout from said cover, the opposite ends of said screen beingdisposed in substantially horizontally spacedapart relation to define anupwardly facing material inlet opening through the top portion of thescreen into the interior thereof,

a material feed chute extending through said cover at the top of saidhousing and leading to said mate- 4-, rial inlet opening to delivermaterial into the region bounded by said screen and said side walls andon top of said hammers, one end of said screen, at one side of saidinlet opening, being closely adjacent said tip plane path and theopposite end of thevscrcen being distantly spaced therefrom, a

and said rotor shaft being rotated in that direction causing saidhammers to pass from said opposite end of the screen and along thelength of the screen in approaching said one end of the screen.

2. In the screening mill as defined in claim 1 wherein said side wallsare provided with ledge means receiving the opposite side edges of saidscreen in slip-fitted relation.

3. In the screening mill according to claim 2 wherein the other of saidside walls is mounted for movement toward and away from said screen.

References Cited UNITED STATES PATENTS Re. 21,523 8/1940 Elderkin 241861,786,262 12/1931) Poppelman 24 l86 1,911,718 5/1933 Saunders 241862,253,087 8/1941 Neal 241-88 3,169,711 2/1965 Helms 241--9) FOREIGNPATENTS 583,515 12/1946 Great Britain.

ANDREW R. JUHASZ, Primary Examiner.

WILLIAM W. DYER, JR., Examiner.

R. J. ZLATNIK, Assistant Examiner.

